I think this may be Bednall Beauty , which has a less symmetrical flower and a smaller eye.

With Dahlias, I usually stake to about one third to one half the height of the plant to keep it more upright, but the bishop is usually pretty well behaved in this regard, and deadhead to extend the flowering period and quality.

However if you dry the seed out you would be amazed at the success from seed , nearly 100%, and the new plants will sometimes be true enough with some surprises.

Cantillon, I find your comments rude, destructive and arrogant, like people differ so will be their style of gardening, and it is not up to anyone to dictate how someone has to garden. I would say Oku's picture shows a natural style of gardening, one I personally find more attractive than over-tidy gardens, needing a constant fight with nature instead of working with nature..

This is quite definitely Bishop of Landaff, the individual flower head picture should make that clear. Bear in mind I am growing mine in the UK, not the USA. I also grow Bishop of York.
I have an old fashioned English cottage style garden, things either grow or they don't and I avoid like the plague things that need staking. the Bishop has been happily growing in that spot now for 7 years. It is never lifted and has survived in situ 3 of the coldest winters in recent history and the wettest summer too. My soil is light and sandy so it drains extremely well ( not to say too well!) which is how my dahlias cope with being left in place in winter.